Project Summary Despite great efforts to incorporate the vast amount of clinical and molecular data describing oral squamous cell cancer (OSCC), few improvements have been achieved and implemented successfully into the clinic. New ways to interpret and interrogate the data on OSCC are required to address the challenges posed by poor treatment outcomes, severe side effects of most current therapies and high costs. Recent advances identifying changes in the oral microbiome and its association with disease, prompt our goal to a better understanding of interactions between the normal oral epithelium with resident bacteria. E-cigarette (E-cig) use, similar to smoking, induces DNA damage and most likely initiates the carcinogenic process. However, its effects also alter the oral microbiome which leads this proposal to address the role of E-cig vape as initiator of OSCC, by defining its effect on oral epithelial cells and oral commensals and tumor associated bacteria. We hypothesize that E-cig nicotine vape modulates host-microbe interaction by inducing a bacterial stress response and consequently inducing epithelial cell inflammation and proliferation. Crosstalk between the microbiota and the host involves inflammatory responses, for which limited in vitro models exist and better tools are necessary to fully investigate the effects of colonizing bacteria in both normal and dysbiotic environments. We propose to formally address the question of what stress responses select microbes have upon vape exposure and host cell exposure, and how those responses alter the default host cell responses to the same irritant. We aim to address these questions using novel bioengineered tissue models such as physiologically relevant organotypic cultures and three-dimensional spheroids to expose E-cig nicotine vape in a specifically designed smoke chamber. Aside from functional assays to assess inflammation, proliferation and stemness, we will identify expression changes using whole genome sequencing. The goal is that upon completion of these experiments, we have a better understanding of bacterial contribution to oral carcinogenesis in the context of E- cig vape. Subsequently, there is an unmet need for controlled experimental systems of host-microbiome interactions that allow for the discernment between cause and effect. The interdisciplinary nature of the Graduate Program and the presence of formal and informal mentoring and training opportunities, e.g. seminars, workshops and mandatory CITI training will contribute to Ms. Catala?s success. Furthermore, the environment provided for these studies here on the UCF campus is ideal: seven investigators of the Burnett School?s Molecular Microbiology Division and additional Cancer Research faculty have interests in environmental risk factors and their modulation of host-microbial interactions. Between the collaborative effort in our labs, and the existence of equipment core and the polymicrobial laboratory space, all the necessary components to accomplish the proposed research goal are available to her.